docs: def getInstance(self, aLocation, axisOnly=False, getFactors=False):
  
          """ Calculate the delta at aLocation.
              *   aLocation:  a Location object, expected to be in bent space
              *   axisOnly:
                  *   True: calculate an instance only with the on-axis masters.
                  *   False: calculate an instance with on-axis and off-axis masters.
              *   getFactors:
                  *   True: return a list of the calculated factors.
          """
          self._collectAxisPoints()
          factors = self.getFactors(aLocation, axisOnly)
          total = None
          for f, item, name in factors:
              if total is None:
                  total = f * item
                  continue
              total += f * item
          if total is None:
              total = 0 * self._neutral
          if getFactors:
              return total, factors
          return total